Conventional narrow band RFI cancellers such as line-interference cancellers eliminate the RFI present in a signal in order to improve the clarity and strength of the signal. Such devices are well known in the art and employ analog techniques to analyze the spectrum of a signal, estimate the level of RFI present in the signal, and then subtract this estimated RFI from the signal.
Such devices are used, for example, as part of communications receivers to eliminate the narrow band RFI generated by power lines. These conventional devices, however, suffer from a significant drawback in that the amount of RFI which can be eliminated is limited. Accordingly, there is a need for a device which can eliminate greater amounts of RFI. Therefore, it would be desirable to provide a canceller which can overcome the drawback of conventional cancellers by employing digital synthesis techniques to eliminate narrow band RFI.